For many manufacturing processes (e.g., thin film deposition processes), it is very important that the mass flow rates of process fluids that are fed into a process chamber be precisely controlled. But many issues arise during ongoing operation of mass flow controllers those adversely affect the ability of mass flow controllers to accurately control mass flow rates.
From the perspective of the user/operator, the particular issues that arise are often not readily apparent or are unexpected, which leads to a high cost of ownership due to unscheduled maintenance. For example, the issues (e.g., minor operating inaccuracies to complete failures) may occur without any immediate indication as to what caused the specific type of undesirable operation. Moreover, users often lack the training, tools, and/or desire to diagnose issues; thus users of mass flow controllers may simply replace mass flow controllers when an issue arises. As a consequence, mass flow controllers are often replaced when information about the underlying problem could lead to a simple remedy. In addition to being an expensive maintenance approach from the user's perspective, the replacement/return of mass flow controllers is also an expensive approach from a vendor's perspective because mass flow controllers may be returned to the vendor that appear to operate normally when tested by the vendor.
If mass flow controllers are not replaced when issues arise, that lack of on-board diagnostic information on mass flow controllers may necessitate that high-cost field service or application engineers visit the user's location to provide on-site tech support and failure analysis once an MFC has been installed. Accordingly, a need exists for a mass flow controller with new and innovative features that enables simpler and more cost effective diagnostic and prognostic analysis.